Microwave coupler



Jan. 22, 1963 TAKAJI KURODA 3,075,158

MICROWAVE COUPLER Filed Sept. 28, '1959 5 3 y b 7 a Inventor 'TAKAJ'I KURDDA Atlorne y United States Patent Japan Filed Sept. 28, 1959, Ser. No. 842,642 Claims priority, application Japan Oct. 31, 1958 3 Claims. (Cl. 333-10) This invention relates to microwave couplers and more particularly to a microwave variable intensity coupler used to obtain varying degrees of coupling between adjacent waveguide sections.

In earlier forms of couplers it was extremely difiicult to obtain a simple and accurate method of varying the degree of coupling between two waveguide sections. The difficulty in attaining sufiiciently accurate coupling adjustments as well as preventing high losses due to the insertion of variable attenuators (it is 'known to obtain the necessary degree of coupling by over-coupling and inserting a lossy element) have been extremely difficult to overcome.

An object of this invention is to provide a microwave coupler which can simply and accurately vary the degree of coupling while avoiding unnecessary consumption of microwave energy by the use of variable resistance attenuators.

The above-mentioned and other features and objects of this invention will become apparent by reference to the fiollowing description taken in conjunction with the accompanying drawings, in which:

FIGS. 1, 2 and 3 disclose cross-sections of difierent embodiments of the present invention.

FIG. 4 is a field distribution diagram illustrating the principle of this invention.

In the figures, references 1 and 2 illustrate adjacent waveguide sections which are mutually coupled. 3 is the coupling hole and 4 is the dielectric body.

Rod 5 and handle 6 are connected to the dielectric body for purposes of positioning the dielectric body about the coupling hole 3.

Waveguides 1 and 2 may be coupled in parallel as shown in FIG. 1 or at right angles as shown in FIG. 3.

The shape of the coupling hole 3 may be a circle as in FIG. 2 or cross-shaped as in FIG. 3, although other shapes may be used. When the dielectric body is placed in the neighborhood of the coupling hole as shown in the accompanying figures the distribution of the electric field in the waveguide varies as shown in FIG. 4. The intensity of the electric field near the coupling hole then changes accordingly, and the degree of coupling between waveguides 1 and 2 varies according to the change of the field intensity.

The dielectric body 4 may be placed inside of waveguides 1 or 2, or a dielectric body may be placed in each.

The position of the dielectric body will determine the intensity of the electric field about the coupling hole 3. As previously explained, one can achieve various degrees of coupling depending on the position of the dielectric body. If desired, a fixed amount of, coupling may be achieved by merely maintaining the dielectric body in a fixed position.

In FIG. 1 the dielectric body may be mounted on rod 5 which is inserted through a wall of one of the waveguides. Thus the position of the dielectric body may be varied about the coupling hole 3 in such a manner that the intensity of the electric field as well as the degree of coupling about this hole may be varied.

In FIGS. '2 and .3, the dielectric body is attached to a pair of rods '7 and 8, which are inserted through a wall of one of the waveguides. A handle 6 is provided so that the dielectric body may be moved to any desired position in order to obtain varying degrees of coupling.

it should also be noted that reflections may be considerably reduced by tapering the shape of the dielectric body.

According to the present invention the coupler and its variable parts are almost integral thus enabling the size of the coupler to be considerably reduced.

While I have described above the principle of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. A microwave variable intensity coupler comprising two contiguous waveguide sections having their major axes disposed in separate planes and having a common aperture therebetween, a dielectric body moveably mounted in at least one of said waveguide sections, and means fior moving said body in a direction parallel to the plane of the surface containing the aperture and transverse the longitudinal axis of said one waveguide section.

.2. A microwave variable intensity coupler as claimed in claim 1 in which the aperture falls within the ends of the dielectric body projected toward the hole.

:3. A microwave variable intensity coupler as claimed in claim 1 in which the plane defined by the greatest surface of the dielectric body intersects the aperture during at least a part of the travel of said body.

References Cited in the file of this patent UNITED STATES PATENTS 2,427,106 Landon Sept. 9, 1947 2,579,327 Lund Dec. 18, 195.1 2,630,492 M-uchmore Mar. 3, 1953 2,812,500 Riblet Nov. 5, 1957 2,849,683 Miller Aug. 26, 1958 2,948,863 Honda Aug. 9, 1960 

1. A MICROWAVE VARIABLE INTENSITY COUPLER COMPRISING TWO CONTIGUOUS WAVEGUIDE SECTIONS HAVING THEIR MAJOR AXES DISPOSED IN SEPARATE PLANES AND HAVING A COMMON APERTURE THEREBETWEEN, A DIELECTRIC BODY MOVEABLY MOUNTED IN AT LEAST ONE OF SAID WAVEGUIDE SECTIONS, AND MEANS FOR MOVING SAID BODY IN A DIRECTION PARALLEL TO THE PLANE OF THE SURFACE CONTAINING THE APERTURE AND TRANSVERSE THE LONGITUDINAL AXIS OF SAID ONE WAVEGUIDE SECTION. 